Host – Dan Keller
Hello, and welcome to Episode Ninety-six of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m Dan Keller.
Today's interview features Drs. Bibiana Bielekova, who is an investigator at the National Institutes of Health, and Mika Komori, a postdoctoral fellow in her lab. We caught up with the two physician-researchers at the ACTRIMS meeting in New Orleans earlier this year. At the meeting, Dr. Komori talked about a new and more sensitive way to evaluate what may be happening in the brains and spinal cords of people with progressive MS.
In a recent study, she examined samples of cerebral spinal fluid, or CSF, collected through a thin needle near the base of the spine. She was scouting for immunological biomarkers of progressive MS. In the analysis, a molecule called CD27, mostly from T cells, stood out, as did another marker specific to B cells. Even more revealing was the ratio of the CD27 molecule to the T cells. T cells are a big player in relapsing MS and not usually associated with the progressive, more neurodegenerative forms of MS. The unexpected results raise new questions about why immune-modulating drugs do not seem to be effective against progressive MS.
If validated, the new test may lead to better diagnosis and treatment of people with MS and other neurological disorders. And it may speed up clinical trials in progressive MS and reduce their cost. In fact, the same research team used their new biomarker test in a small phase 2 study of the anti-B cell drug, rituximab, delivered both intravenously in the blood and intrathecally in the spinal column. Unfortunately, the new biomarker test showed that the double delivery system did not work as expected to eliminate inflammatory B cells trapped in the brains of people with progressive MS. They stopped the study early for lack of efficacy.
In a change to our usual podcast format, Dr. Bielekova interviewed Dr. Komori about the specifics of the study and put the results in a larger context. Midway through the interview, Carol Morton, a past editor of MS Discovery Forum, asked both doctor-scientists about what the new test means for treating patients.
Interviewer – Dr. Bibiana Bielekova
As a physician, when we see patients, we don’t really know what’s happening in their brains, right? We are using some tools that are supposed to help us to identify like, for example, MRI, but they are not perfect. So, how did you choose to address that problem?
Interviewee – Dr. Mika Komori
So, when I saw patients, I can’t tell them that the drug, which are now available, is effective or not, especially for progressive MS patients, because currently so far all big clinical trials, they didn’t show any effects on them. Because of that result, we think progressive MS patients don’t have any intrathecal inflammation. So far we believe MS – multiple sclerosis – is inflammatory disease, but we don’t know if it’s true for progressive MS or not.
Yes, and, in fact, it is because these tools are not that ideal, right? So, in fact, by using the tools that are available, such as MRI or these cerebrospinal fluid markers that have been developed more than 40 years ago, the conclusion is that there isn’t inflammation in progressive MS, right, because all of them are basically decreased, with exception of IgG index which, as you said, remains stable for many, many years. So somebody who had, for example, infection during childhood can have elevated IgG index for the rest of their life.
So that was really the reason why we wanted to develop something that is more sensitive. And also, I think, the question really was, does cerebrospinal fluid reflect what’s happening in the brain tissue? And can we somehow develop technology that can tell us what is happening in the brain tissue without taking, of course, the biopsy, which is extremely invasive, and we cannot really use it in people, right? So how did you address that problem?
We developed a very good way to measure soluble biomarkers in the CSF with a new technique called Meso Scale Discovery.
So I think we should probably step back a little bit and say that our goal was to really look at the biomarkers that can point towards a specific cell, right? Because there are proteins that can be released by all immune cells, such as for example, chemokines, and, in fact, the vast majority of cytokines. But we were especially interested in looking at the proteins than can specifically point to one particular cell type, and so you did something else to really measure that, right? In fact, we all helped you to do that because it was so difficult, right? So we employed the whole lab to do the separation of cells. And then you were looking at which cells are producing these biomarkers.
So tell us about those three that really panned out as the best.
When we see the results of soluble CD27, soluble CD14, and soluble CD21, soluble CD27 correctly identified all inflammatory neurological disease and also only negative for noninflammatory neurological disease patients.
Whereas all of the traditional markers together, if we put all of them together, they could identify only about two-thirds of the patients. We were really surprised, because – I mean, the field believed, as Mika had said, right, based on the fact you no longer have contrast-enhancing lesions; the treatments no longer work; you don’t have clear cytosis, meaning a large number of white blood cells in the cerebrospinal fluid – the field and us, we believed that what we are going to see, once Mika unblinds these two cohorts of close to 200 patients each that we will see that progressive patients have significantly lower amount of inflammation. But that’s not what she saw. She saw something completely different and surprising. So what did you see?
Well we saw almost comparable level of intrathecal inflammation in both PPMS/SPMS to RRMS.
Not almost, right? There wasn’t any statistically significant difference.
So on the group level, we saw the same level.
Absolutely. Yes, and it was so significant compared to a healthy donor and noninflammatory neurological diseases. So all healthy donor and neuro-inflammatory neurological diseases, they didn’t have high level of especially soluble CD27. But almost 90% of each MS subtypes had very high soluble CD27.
But when you did the ratios…
Then we did the ratio and calculated soluble CD27 per T cell in CSF. We found that even higher level of ratio results in progressive MS patients, both in primary progressive and secondary progressive. And for our MS patients the ratio is almost comparable to healthy donor and noninflammatory neurological diseases. That means, although we don’t see many immune cells in the CSF for progressive MS patients, those cells are in the CNS tissue. And it cannot move, but just shedding the soluble markers like soluble CD27 into the CSF. And we can detect that marker when we measure the CSF.
And I think it really nicely ties with the beautiful pathology studies that have been published that demonstrate that patients with progressive MS no longer have this very dense inflammation around the vessel, which is the type inflammation that is capable of opening blood-brain barrier, right? Which means that that’s the type of inflammation that is associated with contrast-enhancing lesions. But instead, when pathologists looked at normal-appearing white matter, they could see, you know, one T cell here, one T cell there, right? It’s really difficult to quantify it on the pathology level, because they never assay the whole brain. But your assay is, in fact, looking at the entire brain. And what your assay is saying is that the number of cells is basically the same in all of these different stages of MS disease process. What is really different is where they are located, right?
So, in relapsing/remitting MS, they are located in the perivascular aggregates, not much in the normal appearing white matter. That’s where they open the blood-brain barrier. But in the progressive MS they are located in the brain. And I think our conclusion was that, in fact, this may be the major reason why current treatments are not working for progressive MS, because basically we would expect that only those drugs can work in progressive MS that have very good penetrance into the brain tissue.
Now, I think that we also have to realize that just the presence of the cells in the tissue doesn’t tell us that they are pathogenic, right? So it may be that they are there, but something else is driving disability. But on the other hand, the data we have, for example, from recently announced ocrelizumab trial is really suggesting that these cells are indeed pathogenic, right? So I think that we can say that progressive MS is neurodegenerative disease only if we can eliminate inflammation from the brain of progressive MS patients, and it does not translate into stopping disability or significantly inhibiting disability.
But the data that we have published, and we are still collecting, are really suggesting that current treatments, in fact, do not eliminate cells from the brain of progressive MS patients, right? So I think the question of compartmentalized inflammation versus neurodegeneration in progressive MS is really open. And I mean my view is that probably both of them are going to be important, right? I think that just because there are immune cells in the CNS tissue, it doesn’t necessarily mean that neurodegeneration is also not present. But I think the hypothesis that progressive MS is no longer inflammatory disease, and it’s pure neurodegenerative disease – I think that hypothesis is, at the moment, not confirmed, right, because we don’t have the experiment where we would eliminate the inflammation.
So both of you are physicians. Does this influence how you would treat people with progressive MS at all?
Yes, absolutely. So from now, when I see high ratio results of progressive MS patients – soluble CD27 per T cell – if they have high ratio, then I will not treat them with current immunomodulatory drugs. But may be a good idea to try more effective drugs to penetrate in the brain. But if the progressive MS patients, although they have high soluble CD27 but low ratio results, then it will be worthwhile to use some immunomodulatory drugs for them.
I would even kind of take a step back and say that in order to be able to use your tool for the treatment decision, I think we need to gain another type of knowledge which we don’t have yet and that is what are current treatments really doing on these type of assays and this type of pathology, right? So we really need to quantify each individual drug, how much it can affect intrathecal inflammation in patients with the open blood-brain barrier, where the drug actually can get into the tissue versus patients with closed blood-brain barrier, where potentially the penetrance is much, much, much more limited, right. I think that it brings back that case that I mentioned where, you know, we are using, for example, cyclophosphamide, and we are assuming that just because the drug is inhibiting immune response in the blood, it will inhibit immune response in the cerebrospinal fluid. And I think that those assumptions are just not tested, right? And, in fact, when we tested them, we realized that the effect on the intrathecal inflammation is extremely limited.
So I think that there is a knowledge that we need to gain, which is this knowledge of which MS drug is doing what. And, if we conclude that they are not doing a sufficient job, which I am afraid that’s going to be the conclusion, then we can use this technology to in fact develop new drugs, right? Because your technology is looking at the type of inflammation that cannot be measured by contrast-enhancing lesions. In fact cannot be measured by anything that we have available thus far, right? So how are we going to even try to develop new drugs for progressive MS?
Well, we can do it by doing large, Phase 3 trials like we have been doing thus far and looking at disability. But of course, that’s incredibly expensive, and it’s just very inefficient way to do it. So instead, doing small trials where you take patients because they have intrathecal inflammation, right. So you now measure; (A) how much inflammation; and (B) its compartmentalized inflammation. Then you can give them the drug, and then you say, ‘okay so now I’m going to measure’ – and you can do it in 3 months or 6 months, in much, much, much shorter time periods – and say, you know, ‘how much is this drug inhibiting intrathecal inflammation?’ And, in fact, that’s precisely what you have done in our RIVITALISE trial, right? Which, unfortunately, we stopped precisely because your assays determined that we are not achieving as much inhibition of inflammation as we were hoping to achieve. So I think that that makes drug development very efficient. And hopefully it will allow us as a society, to screen many, many more treatments on a yearly basis than what we can do currently.
I think if we can measure the cell-specific or pathophysiology-specific biomarkers, we can combine treatments.
If, like interferon, it doesn’t work, let’s try natalizumab. If not, let’s try this, but if we know that interferon works for this side of the pathophysiology, but natalizumab works for this side of the pathophysiology, then we can combine them to more effective treatment.
Yes, and I think that I would say ‘more to come,’ right? So far Mika published data that relate to inflammation, but the lab is working very hard on biomarkers that reflect, for example, mitochondrial dysfunction, or neurodegenerative processes. And we absolutely believe that treatments will have to be combined, and that this, you know, basically assaying cerebrospinal fluid is going to be that tool that will, on one hand allow us to develop these new treatments, and on the other hand, allow us to treat patients smartly at the bedside.
Thank you for listening to Episode Ninety-six of Multiple Sclerosis Discovery. This podcast was produced by the MS Discovery Forum, MSDF, the premier source of independent news and information on MS research. Msdiscovery.org is part of the nonprofit Accelerated Cure Project for Multiple Sclerosis. Robert McBurney is our President and CEO, and Hollie Schmidt is Vice President of Scientific Operations.
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For Multiple Sclerosis Discovery, I'm Dan Keller.